fix PR gdb/17130

This fixes PR gdb/17130.

The bug is that some code in utils.c was not updated during the target
delegation change:

  if (job_control
      /* If there is no terminal switching for this target, then we can't
         possibly get screwed by the lack of job control.  */
      || current_target.to_terminal_ours == NULL)
    fatal ("Quit");
  else
    fatal ("Quit (expect signal SIGINT when the program is resumed)");

After the delegation change, to_terminal_ours will never be NULL.

I think this bug can be seen before the target delegation change by
enabling target debugging -- this would also cause to_terminal_ours to
be non-NULL.

The fix is to introduce a new target_supports_terminal_ours function,
that properly checks the target stack.  This is not perhaps ideal, but
I think is a reasonable-enough approach, and in keeping with some
other existing code of the same form.

This patch also fixes a similar bug in target_supports_delete_record.

2014-07-18  Tom Tromey  <tromey@redhat.com>

	PR gdb/17130:
	* utils.c (quit): Use target_supports_terminal_ours.
	* target.h (target_supports_terminal_ours): Declare.
	* target.c (target_supports_delete_record): Don't check
	to_delete_record against NULL.
	(target_supports_terminal_ours): New function.

1 files changed, 5 insertions, 0 deletions

diff --git a/gdb/target.h b/gdb/target.h
index 8c8ce00..35a7d7d 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1397,6 +1397,11 @@ extern void target_terminal_inferior (void);
 #define target_terminal_ours() \
      (*current_target.to_terminal_ours) (&current_target)
 
+/* Return true if the target stack has a non-default
+  "to_terminal_ours" method.  */
+
+extern int target_supports_terminal_ours (void);
+
 /* Save our terminal settings.
    This is called from TUI after entering or leaving the curses
    mode.  Since curses modifies our terminal this call is here